UK Weather and Climate

UK Climate Overview

The UK has a temperate maritime climate — characterised by:

• Mild temperatures: rarely very hot or very cold; average annual temperature ~9°C (range: 3°C winter to 18°C summer in England)
• Rainfall throughout the year: no true dry season; annual average ~900 mm (range: 600 mm in SE England to >3,000 mm in the Scottish Highlands/Snowdonia)
• Prevailing south-westerly winds from the Atlantic Ocean
• Frequent cloud cover and changeable weather: the UK sits at the meeting point of several air masses

This climate is determined by the UK's latitude (~50–60°N), position on the western edge of a continent, proximity to the North Atlantic Ocean and the North Atlantic Drift (a warm ocean current that keeps winters much milder than other places at the same latitude, e.g., Moscow).

Air Masses Affecting the UK

An air mass is a large body of air with relatively uniform temperature and humidity, derived from the region over which it originates. Five main air masses affect the UK:

Factors Influencing UK Climate

Distance from the Sea

• Maritime influence: Western UK (Wales, W Scotland, W England) is wetter and has a smaller temperature range because the ocean moderates temperatures
• Continental influence: Eastern UK is slightly drier and has greater temperature extremes (warmer summers, colder winters)

Relief (Altitude and Aspect)

• Orographic (relief) rainfall: moist south-westerly air is forced to rise over mountains → cools → condenses → heavy rain on windward (west-facing) slopes (Snowdonia, Lake District, Scottish Highlands)
• Rain shadow: eastern slopes receive far less rainfall after air descends and warms
• Altitude also lowers temperature: approximately −0.6°C per 100 m gain

Latitude

• Southern UK is warmer than northern UK due to the sun's angle being higher in the sky → more concentrated solar radiation

The North Atlantic Drift

• Warm ocean current flowing NE from the Gulf of Mexico
• Keeps UK winters 10–15°C warmer than expected for the latitude
• Without it, UK winters would resemble Newfoundland (~−20°C)

UK Extreme Weather Case Study: The 2014 Winter Floods

Winter 2013–14 was one of the UK's wettest on record. A persistent series of Atlantic depressions (low-pressure systems) driven by an unusually strong jet stream brought exceptional rainfall to the UK:

Somerset Levels:

• Low-lying agricultural land in Somerset — naturally prone to winter flooding
• December 2013–February 2014: flooded for more than 10 weeks (unprecedented)
• Cause: exceptional rainfall (250%+ of normal January rainfall); rivers (Tone, Parrett) could not drain the land fast enough
• Effects: 600+ homes flooded; farmers lost livestock and crops; road closures isolated villages
• Management: Army deployed; emergency pumps installed; Levels were drained by March 2014; £100 million spent on Somerset Levels flood management since

Storm St Jude (October 2013):

• Severe ex-hurricane extratropical storm; 100 mph gusts in SE England
• Disrupted transport; roof/tree damage; 4 deaths in England; uprooted 50,000+ trees

UK Extreme Weather: Recent Trends

Climate change is making UK extreme weather events more frequent and intense:

• 2022 UK heat wave: 40.3°C recorded at Coningsby, Lincolnshire — first ever >40°C in the UK; 2,500+ excess deaths; infrastructure failures (melted roads, buckled rails)
• 2019–20 winter storms (Ciara, Dennis): widespread flooding — Pontypridd, South Wales particularly badly affected
• 2018 "Beast from the East": sudden stratospheric warming brought very cold Polar Continental air — heavy snow, −10°C; major disruption
• Summer droughts: 2018 and 2022 saw record dry conditions in many regions

WJEC Exam Tips

• Know the five UK air masses by name and their characteristics
• For an extreme weather case study: learn causes, effects and responses — the classic WJEC structure
• Be able to explain why the west of the UK is wetter than the east (orographic rainfall + prevailing winds)
• Climate and weather are different: climate = long-term averages; weather = day-to-day conditions